Option 2; 2017 and prior versions may not include the options to setup your VM Options and Properties in the configure menu. Instead:

Create New Project

Help > Edit Custom VM Options

Help > Edit Custom Properties

Chromium in CLion

Import project

At the startup dialog, select Import Project and select your chromium directory; this should be the parent directory to src. Selecting src instead would result in a bunch of CLion IDE files appearing in your repository.